I am careful in winter to be still as snow when I’m near my hives. As the weather gets colder and colder, the bees begin their journey to their inner world. Bees in cluster are suspended in a quiet time much like meditation. Any disturbance, like knocking against the hive or stomping nearby, may rouse them up. Rousing is not good in cold weather.
If you have an observation window on your hives, resist the temptation to open it in winter. I know, I know, it’s hard not to open the window and have a look. Don’t do it. Window viewing is for warm seasons. In winter the bees turn their metabolism way down, just shy of hibernation but where they can still move around. The slower metabolism keeps them from expending energy or needing much food. When bees are in that suspended dreamy place, any jarring sound or light from an opened window could yank them out of their torporous state as rouse to figure out how they should respond to the intrusion. Let them rest. If they are roused too much, they may wake and can eat all their honey stores before spring arrives.